1. Field of the Invention
The present invention relates to a drum type washer, and more particularly, to a helical core configuring a stator of an outer rotor type BLDC motor and fabricating method thereof.
2. Discussion of the Related Art
Generally, a drum type washer performs washing in a manner of rotating a drum, in which a laundry, detergent, and water are put, by a drive force of a motor using friction between the water and the laundry. The drum type washer causes almost no damage to the laundry, prevents raveling of the laundry, and bring about effects of beating and rubbing.
Drum type washers are categorized into an indirect coupling type and a direct coupling type according to a drive system. In the indirect coupling type, a drive force of a motor is indirectly transferred to a drum via a motor pulley and a belt wound of the drum pulley. In the direct coupling type, a rotor of a BLDC motor is directly coupled with a drum to directly transfer a drive force to the drum.
Yet, in the indirect coupling type system that transfers the drive force of the motor to the drum via the motor pulley and the belt wound on the drum pulley instead of transferring the drive force of the motor to the drum directly, energy loss occurs in the process of drive force transfer and considerable noise is generated.
Hence, the direct coupling drum type washer using the BLDC motor is widely used to solve the above problems of the drum type washer.
FIG. 1 is a cross-sectional diagram of a direct coupling drum type washer according to a related art.
Referring to FIG. 1, a tub 2 is provided within a cabinet 1, and a drum 3 is rotatably provided within the tub 2.
A motor is provided to a rear portion of the tub 2. Specifically, a stator 6 is fixed to a rear wall of the tub 2 and a rotor 5 encloses the stator 6 to be coupled to the drum 3 via a shaft.
A door 21 is provided to a front portion of the cabinet 1 and a gasket is provided between the door 21 and the tub 2.
A hanging spring 23 supporting the tub 2 is provided between an inside of a top portion of the cabinet 1 and an upper outer circumference of the tub 2, and a friction damper 24 is provided between an inside of a bottom portion of the cabinet 1 and a lower outer circumference of the tub 2 to attenuate vibration of the tub 2.
FIG. 2 is a perspective diagram of a stator in FIG. 1 and FIG. 3 is a perspective diagram of a sectional core (SC) applied to the stator in FIG. 2.
A method of manufacturing a stator core according to a related art is explained as follows.
First of all, a plurality of unit cores are fabricated by a pressing process of a steel plate. In doing so, each of the unit cores consists of teeth 151, a base 150, and a protrusion 500 opposite to the teeth 151 for forming a locking hole 500a. A plurality of the unit cores are stacked to form a plurality of assemblies. And, a plurality of the assemblies are linked in a circumferential direction to complete a stator core.
The protrusion 500 plays a role in standing a locking force of a bolt as well as provides the locking hole 500a necessary for locking a stator to the rear wall of the tub.
Yet, such a method of manufacturing the sectional core SC is very complicated and brings about considerable loss of materials.
Namely, the sectional core SC is manufactured in a manner of preparing one unit core from one steel plate by pressing, stacking a plurality of the processed unit cores to form a plurality of assemblies, and linking a plurality of the assemblies to one another in a circumferential direction. Hence, a considerable amount of the steel plates remains after completion of the pressing to waste the material. Since the protrusion 500 located opposite to the teeth 51 is provided to the unit core, a considerable size of the steel plate is needed to manufacture the unit core. And, the manufacturing method is complicated as well.
Hence, a new stator core playing the same role of the sectional core SC is needed to reduce the material loss and to simplify the corresponding manufacturing process.